Downloads a specific document associated with the provided UUID. This UUID represents a document which could be of type FCCORE_attachment, FCCORE_emailSent, FCCORE_letterSent, FCCORE_smsSent or DASHBOARD_email.

For S3-backed documents, the default behaviour is an HTTP 302 redirect to a signed S3 URL. Set mode=url to return the signed URL in a 200 JSON response instead. FCCORE_smsSent documents return 200 text/plain because SMS content is stored as text rather than an S3 file.

Set parser=email for supported inbound dashboard emails to return rendered 200 text/html content instead of a signed URL or redirect.